The present invention relates to a cryptogram lock system with an automatically variable true random code, and more particularly relates to the controller for said cryptogram lock system.
There are three basic kinds of methods available for existing electronic cryptogram locks to produce their code and the like. One method is to input a code by user making use of a keyboard. According to this kind of method, a user has to remember the code. Thus, the security of the cryptogram lock is rather poor if a permanent code is used, several persons use a cryptogram lock, or a person uses several locks. Even if the code is changed as a security precaution, the user has to relearn a new code each time. In addition, this kind of cryptogram lock is not suitable for elderly people, children or person with lower educational lever because the operation for opening the lock is considered to be too complicated.
Another method is that a permanent code is selected by the user at the time of purchasing a cryptogram lock and the code is stored in the lock and corresponding keys. The code stored respectively in the lock and keys will be automatically compared when the cryptogram lock is opened. This kind of cryptogram lock prevents the user from the problem of having to remember the code, and therefore is widely applicable in the equipment including a magnetic card or an IC card. However, once the key is lost or reproduced by others without authority, the security of the cryptogram lock will be threatened seriously. In other hand, if the code needs to be revised in this kind of cryptogram lock, one must turn to specialist and special devices for help.
The third one is based on the second method to change the code by means of a certain algorithm. According to this method, the code of a cryptogram lock will be changed to a new one automatically or by the user through a specific operation (for example pushing a button) when the cryptogram lock is opened. The dynamic code obtained in this way is helpful for improving the security of the cryptogram lock. However, it is no longer a difficulty nowadays for a person to decipher the code by means of a computer because the code is produced depending on an algorithm.
It is understood, therefor, that the method for producing and managing a code has become the key point on whether electronic cryptogram locks can be popularized to replace the traditional lock and mechanical cryptogram lock.
The purpose of the present invention is to provide a cryptogram lock system with automatically variable true random codes to overcome the aforementioned disadvantages of the prior art. The cryptogram lock system of the present invention may be opened simply in the same manner as the conventional lock without the necessity for the user to input a code, therefore it relieves users from the burden for remembering the code. In addition, the code stored in the memory units of the lock-body as well as the key-body is not a permanent one, but one automatically changed every time after the lock is opened successfully. The code used in the cryptogram lock of the present invention is a true random code. That means there is no any mathematical relationship between the previous code and the new one, which excludes essentially the possibility of deciphering the code by means of a computer. The only possible way for deciphering the code is to make a thorough one-by-one try. As long as the code has enough length, however, the possibility of deciphering through such a try may be reduced to whatever low level as desired. For this reason, the cryptogram lock system according to the present invention may provide ideal safety.
The present invention is applicable for various cryptogram lock systems in form of either conventional lock or remote controlled one.
The cryptogram lock system with automatically variable true random code comprises a lock-body and a key-body with a bidirectional communication link established therebetween (either through connecting wire or radio set). The lock-body comprises a lock mechanism portion and a control portion, wherein said control portion comprises a microprocessor IC1, a non-volatile memory unit IC2, a true random code generator IC3, and an output driver IC5 for driving said lock mechanism portion, and an alarm unit IC6. Said key-body further comprises a non-volatile memory unit IC4.
The cryptogram lock system of the present invention operates in the following manner. At first, a code is stored respectively in the non-volatile memory units IC2 and IC4 of the lock-body and key-body. When a communication link is established between the lock-body and the key-body, the microprocessor IC1 within the lock-body takes out the code stored in the memory unit IC4 of the key-body and compares it with the code stored in the unit IC2 of the lock-body. If the two codes are coincident with each other, the microprocessor controls the driving mechanism to open the lock, otherwise the microprocessor activates the alarm unit to send out an alarm signal. Whenever the cryptogram lock is opened successfully, the microprocessor IC1 takes out immediately a new code from the true random code generator to replace the previous one stored in the memory units IC2 and IC4 so as to make the lock system ready for the next operation. In such a manner, the code used by the lock system can be updated in each opening operation.
In conclusion, the cryptogram lock system of the present invention is characterized in that the code is neither inputted through a keyboard nor stored permanently in the lock system, but generated by a true random code generator. Whenever the cryptogram lock is opened successfully, the microprocessor takes out a new code from the true random code generator to replace the previous one stored in the memory units of the lock-body and key-body, respectively.